Looking to see if I can put something together to turn on reverse lights. We just put a 2016 L86 6.2 Escalade engine in a 1971 GMC Jimmy. We wired in a standalone harness for the engine and 8 speed automatic.
What I would like to do is tie into canbus system , and when the arduino sees the canbus code for reverse it triggers a relay for lights on and when shifted out of reverse the lights go off.
Automotive is full of proprietary hardware, so the first step is to find a hacker forum that specifically deals with mods to that specific make, model and year of ECU and wiring harness.
If you are lucky someone may be able to provide you with a list of CAN codes, otherwise you are going to have to use a CAN bus analyser to figure out what to look for.